hamilton



Feb. 21, 1956 w, 5, HAMlLToN 2,735,961

STARTERS FOR FLUORESCENT LAMPS 2 Sheets-Sheet 1 Filed 001'... 21, 1952 9 Q INVENTOR; Will/am SJ/framflfon,

ATTORNEY Feb. 21, 1956 w. s. H. HAMILTON 2,735,961

STARTERS FOR FLUORESCENT LAMPS Filed Oct. 21, 1952 2 Sheets-Sheet 2 4 1 1L fil /MM? 4 d ing h fljlll ii Fig-5- 5-15- FY .11.

3 I 4 ATTORNEY,

United States Patent 2,735,961 STARTERS FOR FLUORESCENT LAMPS William S. H. Hamilton, Larchmont, N. Y.

Application October 21, 1952, Serial No. 315,984

3 Claims. (Cl. 315-100) This application is a continuation-in-part of my prior application Serial No. 230,185, filed June 6, 1951.

This invention relates to starters for fluorescent lamps, and particularly to starters for use in connection with starting and operating circuits for A. C. and D. C. fluorescent lamps of those types which are more or less diflicult to start and require an inductive kick to start them.

The primary object of the invention is to provide an improved system for starting and operating gaseous electric discharge devices, such for example as fluorescent lamps, which will produce an extremely high inductive voltage surge or kick so as to effectively start lamps that are capable of being started, which will enable the lamps to be restarted quickly after being shut 0E, and which will also automatically and effectively cut out and lock out of operation any lamp which is defective, or incapable of being started for any reason.

Another object of the invention is to provide such a system, wherein, should a lamp be automatically cut out of operation as previously mentioned, no further lighting effect of any kind can be produced by such lamp.

The present invention comprises a system for starting and operating from a supply line a gaseous electric discharge device such as an electric fluorescent lamp having at least two electrodes connected with. the terminals of the line circuit, at least one electrode being adapted to be heated, and preferably of filamentary type, such system or starter embodying preheating and operating circuit connections, a normally closed thermostatic switch and a normally closed electromagnetic switch together with a heater for the thermostatic switch, said switches being arranged for cooperation with each other'and with the circuit connections of the lamp to normally establish the preheating circuit to supply preheating current to the lamp when the line circuit is closed and until the preheating circuit is broken by the opening of the said electromagnetic switch, an electromagnetic operating coil being arranged in the circuit so as to be normally cut out of action and de-energized while the preheating circuit is closed, but to be energized when the thermostatic switch opens and when the lamp passes current, to open the electromagnetic switch and hold it open while the lamp is operating normally, an inductance being arranged in the circuit so that when the electromagnetic switch opens an inductive kick is produced to start the lamp. 7

In the operation of these parts preheating current is supplied to the lamp for a definite period or until the heater causes the thermostatic switch to open and allow the electromagnetic coil to be energized. This causes the electromagnetic switch to open and break the preheating circuit and, since the lamp, if in normal operating condition, will be ready to fire, the inductance will produce an inductive kick to cause the lamp to fire. When the preheating circuit is thus cut out and the operating circuit is in operation the coil is arranged in series in the operating circuit and holds the electromagnetic switch open as long as the lamp is operating.

At the same time the heater is cut out which allows the thermostatic switch to cool off, but the electromagnetic switch mechanically prevents the thermostatic switch from returning to its normally closed position as long as the coil remains energized. Hence, if the line circuit is opened to shut off the lamp, the coil will be de-energized allowing the electromagneticswitch, and also the thermostatic switch to reclose immediately so that the circuit will be ready to immediately commence a restarting action. Thus there is no time lost in waiting for the contacts of the starter to return to their starting position as is the case with the usual type of starter employing a normally closed thermostatic switch, whose heater coil remains in the circuit while the lamp is burning.

The invention comprises means in the form of a second thermostatic switch, and heating means therefor,

operating under abnormal conditions caused by repeated attempts to start the lamp, if the lamp is defective or has outlived its useful life, to cut the preheating circuit out of action and keep it out of action as long as the line circuit is closed and until it is opened, in order to prevent possible injury to the starter and circuit components.

The invention further includes a circuit arrangement and cut-out means which are operative to disconnect one terminal of the supply line from the lamp, thereby eliminating the possibility of a potential difference between the lamp electrodes which might cause the phenomenon known as ghost lighting.

Certain of the circuits used for operation of fluorescent lamps on D. C. may be so constructed as to permit passage of current through the starter and gas in the lamp simultaneously with and in addition to application of preheating current to the negative filament. This feature is advantageous in giving more light from the fixture before the lamp fires and in providing a better indication that the lamp will shortly fire, than is given by the passage of preheating current through the negative. filament alone.

Embodiments of my invention are shown in the accompanying drawings in connection with certain of many circuits in connection with which the starter may be used, in which drawings:

Fig. 1 is a diagrammatic viewof a circuit for lamps operating on A. C. employing a reactor-transformer and a starter embodying my'invention which is reversible in its socket, said starter including the quick restarter feature as well as a cut-out or lock-out means of the character described.

Figs. 2 and 3 are similar views respectively showing the starter connections in the normal and reversed posititons of the starter in its socket.

Figs. 4 and 5 are diagrammatic views of circuits for D. C. use employing a plain inductance or reactor and a ballast lamp and adapted for use with a starter embodying the quick restarter feature but not the lock-out means.

Figs. 6, 7 and 8 are schematic obverse, reverse and side elevational views of a starter embodying the quick restarter feature and the lock-out means, showing only the basic features of the starter and omitting the wiring connections.

Figs. 9 to 12, inclusive, are views of a starter as designed for practical use'in connection, for example, with for the thermostatic switches, which are connected in the manner shown in those circuits employing the switch 3 S3 and its heaters, H2 and H3 for a lock-out action, which switch and its heaters may be omitted from a starter designed for use in circuits not employing a lockout action, the inclusion or omission of such switch and its heaters involving merely changes in the wiring arrangements.

The switches, which are of the self-closing type and normally closed are not physically coupled for conjoint action, but are independently movable, switch S1 under action of the coil C and switches S2, S3, in response to their heaters H1, H2 and H3, with the exception that the quick restarter feature in the form of a mechanical interlocking connection, controlled by the armature actuated by the coil and generally designated MIC in Figs. 1 and 4 to 17, is disposed between switches S1 and S2, and is provided for holding switch S2 open together with switch S1 under the electro-magnetic attraction of the coil C when the coil is energized. Coil C when energized acts only to pull switch S1 open after switch S2 has been thermally opened, .and in such action moves the interlocking connection into position to hold switch S2 in its open position.

This connection comprises an insulated arm A4 carried by the armature switch S1 which normally is free from connection with and allows full opening movement of S2, but which has at its free end a finger or projection which moves into engagement with switch S2 when switch S1 is opened to hold switch S2 open, this holding action being due to the magnetic attraction of the coil. A condenser C omitted in Figs. 6, 7 and 8, but shown in the various circuits, is included in the starter to reduce the arcing at the contacts in accordance with customary practice. A stop A5 is provided to limit the travel of thermal switch S3 when heated.

In the drawings I have shown types of circuits for fluorescent lamps in which the starter A, in the forms disclosed, or by simple changes in the wiring or arrangement of parts, may be used to secure-prompt and reliable starting and rapid restarting actions of a lamp in good order and which may be used to secure a lock-out action to avoid undue repetitive starting attempts if the lamp is defective or has reached the end of its useful 'life period.

Referring to Figs. 1, 2 and 3, showing a circuit for operation of 48", T-l2 lamps, and other like lamps, 5 designates the lamp having filamentary electrodes 6 and 7 which are connected in series for a preheating action, and S and 9 designate the line leads from the line terminals B, W. The circuit includes a reactor-transformer R-T whose primary is connected across the A. C. line and whose secondary is arranged in a conductor 10 connected with one terminal of filament 6. From the other terminal of filament 6 extends a-conductor 11 leading to terminal 1 of the starter between which and the terminal 2 is serially arranged a partof the starter switch circuit including the conductors 12 and 16, the heaters H1, H2, the electromagnetically actuated switch "S1 which normally closes said part of the starter switch circuit, and an arc suppressing condenser C.

Terminal 2 is connected to one terminal of filament '7, the other terminal of which is'connected 'to the terminal 3 of the starter. Terminal 3 in turn is connected to a second part of the starter switch circuit and a cutout or lock-out circuit connected in series with each other and with the starter terminal 4, from which leads a conductor 14 which is connected with the conductor 9 and primary of the reactor-transformer. The second part of the starter switch circuit includes the conductor 13 containing the normally closed time delay thermostatic switch S2, whose heater H1 is arranged in the conductor 12, and the cut-out or lock-out means which includes the normally closed thermostatic switch S3 and one of its heaters, i. e., auxiliary heater H3, which is normally short circuited by cut-out switch S3 except during a cut out action, its other or main heater H2 being connected in conductor 16.

Connected across the time delay switch S2 and normally shunted thereby out of the path of flow of preheating current is a circuit comprising conductors 15, 15' and the relay coil C. The circuit 15, 15 containing the coil forms with conductors 13 and 14 and cut-out switch S3, when switches S1 and S2 are open, part of the lamp operating circuit, which also includes the conductor 8, the reactor-transformer R-T, filaments 6 and 7 and gas or" the lamp 5. When the switches S1, S2 and S3 are closed a preheating or starting circuit excluding the relay coil but including the conductors 1%, i1, 12, 13, 14 and the switches S1, S2 and S3 is formed, which connects both filaments in series with each other and the line, for preheating the filaments when the line circuit is closed. Heater H1 may be an open coil heater of 5-10 ohms resistance. Main and auxiliary heaters H2, H3 are preferably carbon rod resistors of approximately 30,00050,000 ohms each.

In starting, current flows from line terminal B through the reactor-transformer R-T back to the other line terminal W. It also flows through the secondary winding of the reactor-transformer which steps up the voltage above that of the line voltage to conductor 16. Current then flows through filament 6, switch S1, heater H1, and through filament 7 and switches S2, S3 back to line terminal W. As heater H2 is of high resistance compared to heater H1 and is connected across switch S1 and heater H1, it (heater H2) is short circuited and has no efiect on the initial firing. Also as heater H3 is connected across switch S3 it is short circuited until this switch opens.

Current fiows through the circuit until heater H1 heats switch S2 sufliciently to cause it to open its contacts S2, 82'. Opening of switch S2 allows the coil C to be encrgized which causes the coil to break the contacts S1, S1" of switch S1 rapidly, thereby breaking the inductive circuit through the reactor-transformer and causing the lamp to fire if it is a normal one in good condition. The condenser C absorbs the arcing when switch S1 opens. When 'the lamp fires, current flows through conductor 10, filament 6 of the lamp, through the gas in the lamp to the filament 7 and back through the coil C and switch S3 to the line terminal W. When heater 1H1 cools oil, the mechanical interlock MIC prevents switch 32 from reclosing its contacts and short-circuiting the coil C.

It will be noted at this time that heater H2 has some heat applied to it, but this is not enough to cause switch S3 to open. Therefore, if the line current is interrupted coil C will be de-energized and switches Si and 52 will return to the position shown in Figs. 1, 2 and 3, where they are ready to initiate another starting action immediately upon the line circuit being reclosed.

However, if the lamp is defective, or has reached the end of its useful life, it will not fire on the first opening of the switch S1 and may not fire on several other switch openings. The repeated opening and closing of the switch S1 gradually builds up heat in heater H2, inasmuch as the voltage applied across this heater when switch S1 is open and the lamp has not fired, is substantially line voltage and is greater than when the switch S1 is open and the lamp has fired normally. The accumulative .eflfect of this heat finally causes the contacts S3, S3" of switch S3 to open. As soon as this switch opens, heater H3 is cut into the circuit in series with heater H2 and flowof current to the lamp is efifectivcly cut off, as the small current flowing through heater H3 will not maintain the relay in the position where switch S1 is open and this switch accordingly rccloses and shortcircuits heater H2. This increases the current through heater H3 andenables it to keep switch S3 in its open position and the larnpifrom attempting to fire.

Cut-out switch .53 has adesirable function, in addition to that of effecting the Jock-out action. While lamps of the 48", T 12 type allow operation of a'lock-out starter into lock-out position after they have reached the end of their useful life, they may still continue to pass Current at a low value unless one filament is disconnected from the line, which is not efiected at all or with certainty by many starters of this type in general use. This low current passage usually causes flickering or ghost lighting which is annoying and objectionable. My improved type of starter eifectually overcomes this objection as heater H3 will not pass suflicient current to allow this ghost lighting to take place.

After switch S3 has opened, there will be a delay if the line circuit is opened, before the starter returns to its normal position shown in Fig. 1. However, if it is noted that there is a defective lamp in the circuit, and the lamp is replaced by a new lamp, then it is either necessary to remove the starter from its socket for a few minutes or to replace it with a new starter for prompt operation to start the new lamp. If the starter is removed for this purpose, it can be used again with some other lamp, as it will not have been damaged in any way.

Fig. 2 shows schematically the arrangementsof parts for current flow when the starter is mounted normally in its receiving socket. Fig. 3 shows schematically the arrangement of the parts for circuit flow when the starter is reversed in the socket.

Figs. 9 to 12, inclusive, show the starter A as constructed for practical use in a socket such as used for an FS-44 starter and particularly for circuits of the kind shown in Figs. 4 and 5, in which figures'the circuit arrangements and construction of the parts of the starter are designated by the same reference characters. The starter as so constructed is shown as built without the lock-out feature, but may include this feature if desired, so that, as with the starter shown in Figs. 6, 7 and 8, it may be used to secure a lock-out action to avoid undue repetitive starting attempts if the lamp is defective or has reached the end of its useful life period.

The circuits shown in Figs. 4 and 5 are of simpler construction than that shown in Fig. 1, but may be used with a starter constructed as shown in Figs. 6, 7 and 8 or with a starter constructed as shown in Figs. 9 to 12, inclusive, the starter having a four-pin base and including or not the lock-out feature involving the switch S3 and its heaters H2 and H3 and their wiring connections. The thermal element or switch S3 and its heaters H2 and H3 may be used in the starter construction shown in Figs. 9-l2 when a lock-out action is desired or is for any purpose required. 7 v

In Fig. 4, showing acircuit designed for use with lamps on D. C., a reactor R and a ballast lamp BL are arranged in lead 8' between the positive line terminal and a lead 8 extending to the electrode 7, which is short-circuited, said conductors being coupled through connection 14' with the starter terminal 1. A conductor 9 leads from the negative terminal of the line to starter terminal 3, and a conductor 19' leads from the starter terminal 2 to the input end of electrode 6, which is connected at its output end by conductor 11 to the starter terminal 4. Switch S1 is arranged here to normally connect conductors 12', 13 leading respectively from the starter terminals 1 and 2 and forming therewith one branch of the preheating or starting circuit, while the thermostatic switch S2 is arranged to normally connect conductors 15, 15' leading from the starter terminals 4 and 3 and forming the other branch of the preheating'or starting circuit. In the conductor 12' is arranged the heater H1 and across the conductors 12' and 13' is arranged the arc-suppressing condenser C; while the coil C is arranged in a connection across the conductors 15, 15 so as to be short-circuited as long as switch S2 is closed.

In starting, preheating current flows from the positive side of the line through the reactor, through the ballast lamp BL, to terminal 1 of the starter, through heater H1, through the switch S1, to terminal 2 of the starter,

6 through conductor 10' and the negative filament of the fluorescent lamp and conductor 11, to terminal 4 of the starter, through thermal switch S2 to terminal 3 of the starter, and thence to the negative side of the line. At this time the relay coil C is short-circuited by thermal switch S2.

A connection8 is also made to conductor 14 between the ballast lamp and starter terminal 1, which extends to the short-circuited positive filament of the fluorescent lamp. It should be emphasized in this connection that the positive filament of the fluorescent lamp may be short-circuited or left open circuited as in the circuit of Fig. 5, depending on the characteristics of the different types of lamps within which these circuits are used.

Returning now to Fig. 4, preheating current continues to flow until heater H1 heats thermal element S2 sufficiently to cause it to open its contacts. When this occurs, coil C is cut into the circuit and opens switch 51 by magnetic action, breaking the circuit between the positive side of the line and the negative filament rapidly, and causing the reactor to give an inductive kick to start the lamp.

This causes the lamp, if in good'condition, to fire and after it has fired, operating current flows from the positive side of the line, through the reactor, through the ballast lamp, to the positive filament 7 of the fluorescent lamp, through the gas in the lamp itself to the negative filament 6, thence to terminal 4 of the starter, through coil C to terminal 3 of the starter and thence to the negative side of the line. Coil C being energized, holds switch S1 open directly by magnetic action, and by means of the mechanical interlock MIC it also holds thermal switch S2 open, so that its contacts S S cannot reclose after heater H1 cools off.

If while the lamp is operating normally, the line circuit is opened, coil C immediately allows switch S1 to reclose and through the mechanical interlock MIC also allows thermal switch S2 to reclose, so that the starter is ready for another restarting action as soon as the line circuit is reclosed. No time is lost waiting for a thermal element to cool off, as in a straight thermally operated starter.

If the lamp does not fire on the first attempt, the above starting action is repeated until the lamp either fires, or shows by continued applications and removals of current, that it is a defective one and should be replaced.

In this arrangement the ballast lamp is in the circuit during starting and regulates the amount of preheating current as well as the amount of operating current after the lamp has fired.

Fig. 5 shows a circuit generally similar to that shown in Fig. 4 and in which like parts are designated by the same reference characters, the difference being that electrode 7 instead of being shorted has one of its terminals connected with conductor 8 and the ballast lamp BL is arranged in conductor 6 and that conductor 10 extending between the starter terminal 2 and electrode 6 contains a current limiting resistor R1.

It will be noted that this circuit differs from that shown in Fig. 4 in that the ballast lamp is not included in the circuit during starting. This enables the preheating current to be regulated by the resistor R1 and the operating (or running) current to be regulated by the ballast lamp, separately from each other, which is a flexible and desirable arrangement.

The operation of the starter is the same as that shown in Fig. 4 and heretofore described in detail. I

The contacts S2 and S3" of switches S2 and S3 shown in Figs. 6, 7 and 8 may be thermally responsive or bimetallic contacts if designed to remain closed at varying ambient temperatures. In Figs. 9 to 12, inclusive, both contact elements of the switch S2 are bimetallic and thermally responsive in character and therefore automatically compensate-for varyingarnbient temperatures. :In practice contacts :82 and S are formed of pieces of silver alloy wire weldcdcnto the bimetallic strips S2, S2". The movement of both metallic strips when heated is toward the base A". When heated by ambient temperature, the movement of each is the same and indie same direction, so that contacts S2 and S2 remain in contact. When, however, strip S2 is heated by heater S1, it moves away from the other strip so that contacts S2 and 82 open. Silver alloy contacts are also provided for S1 and S1, but no thermal feature is involved. When switch S3 with its heaters H2 and H3 is required, the contacts 53 and S' may also be mounted on bimetallic strips so that they will remain in contact over a wide range of ambient temperatures of the starter itself.

A starter embodying the present invention has the following major advantages over prior tarters, to wit: (1) The preheating or starting circuit is broken rapidly by the opening of switch Si by magnetic means. T his causes the reactor to give a higher inductive kick than that obtained from the slower opening or straight ther mal or glow switch starters when used the some circuits. The higher inductive kick not only makes the firing more certain, but will also effect the firing of lamps that might be discarded under the impression that they had reached the end of their useful life period. (2) In all normal operation of the lamps, due to the switch S1 being held open magnetically by the coil C by the flow of current through the lamp, the switch will be released imrnediatelyif the line circuit is opened, and in so doing allow switches S1 and S2 to also reclose, so that the starter is ready for another starting action as soon as the line circuit is reclosed. This is not so in the case of a straight thermal starter, where it is necessary for the heater to cool off before its contacts can reclose.

The ability of obtaining a quick resetting action of the parts to obtain an immediate restart applies, of course, to the starters used with or without the lookout feature and when the starter is used with a good lamp. In the case of the use of the starter having the lock-out feature however, the thermal units used for the lock-out action if they come into action take an appreciable length of time (several minutes) to cool oif before a restarting action can take place again. However, this delay :can be avoided, as previously pointed out, when applying a new lamp in place of the defective lamp, by removing the starter which has been in use and applying a new starter, in which case the starter removed may be used as soon as it cools oil in some other circuit.

Having thus described my invention, I claim:

1. In a system for starting and operating an electric discharge device, said system comprising a gaseous elec tric discharge device having two electrodes at least one of which is constructed to receive preheating current, a normally closed electromagnetic switch and a normally closed time delay thermostatic switch having an operating heater, means including an inductance device and the winding of said electromagnetic switch for connecting said electrodes with a source of current supply, a preheating circuit capable of producing firing temperature electrode heating, said circuit extending from one side of said supply source to the opposite side thereof and including in series connection said inductance device said electromagnetic switch, the heater for said time delay switch, said winding and at least one of said electrodes, said time delay switch being connected across said winding so that the opening of said switch introduces said winding into the preheating circuit and causes rapid opening of the-electromagnetic switch to cause the discharge device to fire by an inductive voltage kick, and mechanical means operatively interconnecting said electromagill netic switch and said :tir'ne .zd'elay :therrnostatic switch 10 hold maid latter switch open after :the heater therefor cools, the operating current of said device :continuing' to energize :said winding and hold 'both of said switches open during the operation of the device, and, should the device not fire, .said electromagnetic switch continuing to open and close thereby repeatedly attempting to cause the device to'fire, the combination of mechanism operative after-several such actuations of said switch to prevent further actuation thereof comprising a cut-out thermostatic switch having main :and auxiliary heaters, said switch being connected in a circuit between one of the electrodes and one side of the supply source so that the opening .of said switch disconnects said electrode from the supply source, said cut-out switch also being connectcd in the preheating circuit, and the main heater for said cut-out switch being connected across the electrodes of the discharge device and also across said electromagnetic switch so that the opening of said electromagnetic switch introduces said main heater into the preheating circuit should the discharge device not fire, so that after several actuations'of said electromagnetic switch the cutout'switch is opened by the heat from said main heater, and saidauxiliary heater being connected across said cutout switch so that the opening of said cut-out switch introduces the auxiliary heater into said preheating circuit, the heat from said auxiliary heater maintaining said cutout switch open, said auxiliary heater having a resistance value which limits the current through the preheating circuit to a magnitude insufficient to open said electromagnetic switch.

2. A system for supplying preheating and operating current to a gaseous electric discharge device as claimed in claim -1 in which both of the electrodes of the discharge device are included in the preheating circuit.

3. in a system for starting and operating an electric discharge device, said system comprising a gaseous electric discharge device having two electrodes constructed to receive preheating current, a normally closed electromagnetic switch, a normally closed time delay thermostatic switch having an operating heater, and a cut-out thermostatic switch having main and auxiliary heaters, an inductive device, one terminal of one of said electrodes being connected to one sideof a source of current supply through said inductance device and one terminal of the other electrode being connected to the opposite side of said source through said cut-out switch and the winding of said electromagnetic switch in series connection, said electromagnetic switch and the heater for said time delay switch being in series connection in a circuit connected between the other terminals of said electrodes, said circuit completing a preheating circuit for said electrodes capable of producing firing temperature electrode heating, said time delay switch being connected across said winding so that the opening of said switch introduces said winding into said preheating circuit and causes rapid opening of the electromagnetic switch to cause the discharge device to fire by an inductive voltage kick, and mechanical means operatively interconnecting said electromagnetic switch and said time delay thermostatic switch to hold said latter switch open after the heater therefor cools, the operating current of said device continuing to energize said winding and hold both of said switches open during the operation of the device, and, should the device not fire, said electromagnetic switch continuing to open and close thereby repeatedly attempting to cause the device to fire, the main heater for said cut-cut switch being connected in a circuit which is connected across said electromagnetic switch so that after several actuations of the electromagnetic switch the resulting heat from said main heater causes said cut-out switch to open, and the auxiliary heater for said cut-out switch being connected across said switch so that the References Cited in the file of this patent UNITED STATES PATENTS 2,341,520 Babb Feb. 15, 1944 2,374,315 Whiteside Apr. 24, 1945 2,476,330 Sitzer July 19, 1949 

